So last night the swim team got together for some pizza and to hang out. Being highly intelligent teenagers, we decided to play some pain pong. For those of you who aren't familiar with pain pong, it is a variant of ping pong where everything you loose the point you turn around and your opponent smashes the ball with the paddle at your bare back. Naturally if your quite bad at ping pong(like me) the game can get very painful, but why? Well its because of physics, more specifically impulse!
The impulse or change in momentum is equal to the force applied multiplied by the time of the collision. In the case of ping pong ball hitting my back, the change in momentum is a constant. The force is inversely proportional to the time of the collision. Since the time it takes to stop the ball is quite short, it leads to a large applied force, thus the large welts on my back